Surface Engineering on Commercial Cu Foil for Steering C<sub>2</sub>H<sub>4</sub>/CH<sub>4</sub> Ratio in CO<sub>2</sub> Electroreduction.

Ling, Peiquan; Liu, Yinghuan; Wang, Zhiqiang; Li, Li; Hu, Jun; Zhu, Junfa; Yan, Wensheng; Jiang, Huijun et al. · Nano Lett · 2022

basic_science · Level V

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Abstract

Designing catalysts with high selectivity toward C<sub>2</sub> products in CO<sub>2</sub> electroreduction is crucial to energy storage and sustainable development. Here, we propose a Cu foil kinetic model with abundant nanocavities possessing higher reaction rate constant <i>k</i> to steer the ratio of C<sub>2</sub>H<sub>4</sub> to the competing CH<sub>4</sub> during CO<sub>2</sub> electroreduction. Chemical kinetic simulation demonstrates that the nanocavities could enrich the adsorbed CO surface concentration (θ<sub>COad</sub>), while the higher <i>k</i> helps to lower the C-C coupling barrier for CO intermediates, thus favoring the formation of C<sub>2</sub>H<sub>4</sub>. The commercial Cu foil treated with cyclic voltammetry is used to match this model, displaying a remarkable C<sub>2</sub>H<sub>4</sub>/CH<sub>4</sub> ratio of 4.11, which is 18 times larger than that on the pristine Cu foil. This work offers a handy strategy for surface modification and provides new insights into the C-C coupling and the C<sub>2</sub>H<sub>4</sub> selectivity in terms of mass transfer flux and energy barrier.